Finding the Fourth Proportional to 9,518.72, 13,142.76 and 7,640.63

Step by Step Solution

1. Step 1: Write the proportion equation
   9,518.72 : 13,142.76 = 7,640.63 : x
2. Step 2: Convert to fraction form
   9,518.72/13,142.76 = 7,640.63/x
3. Step 3: Cross multiply
   9,518.72x = 13,142.76 × 7,640.63
4. Step 4: Simplify right side
   9,518.72x = 100,418,921.26
5. Step 5: Solve for x
   x = 100,418,921.26/9,518.72
6. Step 6: Final answer
   x = 10,549.63